The present invention relates to air conditioner/heater and more particularly to a method for controlling the operation of air conditioner/heater by coil temperature.
A conventional air conditioner 1 is shown in FIG. 1 comprising a compressor 11, a heat exchanger (e.g., condenser) 12, a fan motor 13, a filter 14, and a coolant flow controller 15 (all above components are installed outdoors). Air conditioner 1 further comprises a heat exchanger (e.g., evaporator) 16 and a fan motor 17 (both are installed indoors). With this configuration, it is possible to air condition an enclosed space (AO). However, the previous design suffered from several disadvantages. For example, the rotating speed of each fan motor is fixed, i.e., it is not made adaptable to ambient temperature (or coil temperature). As understood that, heat exchange capability of air conditioner is proportional to wind speed which in turn is proportional to motor speed. Thus, heat exchange capability is proportional to motor speed. Hence, the heat exchange capability of the air conditioner is low inherently due to such fixed rotating speed of fan motor, resulting in a waste of energy. Further, the capability of heat dissipation of condenser is always larger than the capability of heat absorption of evaporator. Hence, it is difficult for such conventional air conditioner to operate as heater when desired. Furthermore, the thermal efficiency is unacceptable low even when the air conditioner operates as heater. Thus, improvement exists.
It is an object of the present invention to provide a process for controlling an air conditioner/heater to switch to operate in either an air conditioning mode or a heating mode, the process comprising 1) in the air conditioning mode: sending ambient temperature of at least one enclosed space sensed by at least one sensor to a central processing unit (CPU) for comparison with a default value so that the rotating speed of each of at least one indoor fan motor is proportional to the ambient temperature of the corresponding enclosed space when the ambient temperature of the enclosed space is larger than the default value but smaller than the sum of the default value and a first predetermined offset; 2) in the air conditioning mode: sending at least one outdoor coil temperature sensed by the at least one sensor to the CPU for comparison with the default value so that the rotating speed of each of at least one outdoor fan motor is proportional to the corresponding outdoor coil temperature when the outdoor coil temperature is smaller than the default value but larger than the subtraction of the first predetermined offset from the default value; 3) in the heating mode: sending at least one indoor coil temperature sensed by the at least one sensor to the CPU for comparison with the default value so that the rotating speed of each indoor fan motor is proportional to the corresponding indoor coil temperature when the indoor coil temperature is smaller than the default value but larger than the subtraction of the first predetermined offset from the default value; and 4) in the heating mode: sending the at least one outdoor coil temperature sensed by the at least one sensor to the CPU for comparison with the default value so that the rotating speed of each outdoor fan motor is inversely proportional to the corresponding outdoor coil temperature when the outdoor coil temperature is smaller than the default value but larger than the subtraction of the first predetermined offset from the default value.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.